The 12th International Conference on Environmental ... - Events

Abstracts Session 28-29
<strong>The</strong> Japan Atomic Energy Agency (JAEA) has been developing modelling techniques to overcome these problems as part of
the Mizunami Underground Research Laboratory (MIU) Project in the Tono area of Gifu Prefecture, Japan. An integrated geological
and hydrogeological modelling, and visualisation system referred to as GEOMASS has been developed, which allows for transient
unsaturated groundwater flow modelling in the presence of dynamic underground excavation models. <strong>The</strong> flow simulator in
GEOMASS, FracAffinity, allows for such modelling by the application of sophisticated gridding techniques, allowing for modification
of hydraulic conductivity in key zones, and by suitable modification of water retention models (the relationship between saturation
and pressure, and saturation and hydraulic conductivity).
8) INTEGRATED MODEL OF KOREAN SPENT FUEL AND HIGH LEVEL WASTE DISPOSAL OPTIONS - 16091
Yongsoo Hwang, KAERI (Korea); Ian Miller, GoldSim Technology Group (USA)
This paper describes an integrated model developed by the Korean Atomic Energy Research Institute (KAERI) to simulate
options for disposal of spent nuclear fuel (SNF) and reprocessing products in South Korea. A companion paper (Hwang and Miller,
2009) describes a systems-level model of Korean options for spent nuclear fuel (SNF) management in the 21st century.
<strong>The</strong> model addresses alternative design concepts for disposal of SNF of different types (CANDU, PWR), high level waste, and
fission products arising from a variety of alternative fuel cycle back ends. It uses the GoldSim software to simulate the engineered
system, near-field and far-field geosphere, and biosphere, resulting in long-term dose predictions for a variety of receptor groups.
<strong>The</strong> model’s results allow direct comparison of alternative repository design concepts, and identification of key parameter
uncertainties and contributors to receptor doses.
SESSION 29 - MODELING APPROACHES FOR HLW, SNF, AND TRU WASTE DISPOSITION
1) DEVELOPMENT OF THE ENVI SIMULATOR TO ESTIMATE KOREAN SNF FLOW AND ITS COST - 16060
Yongsoo Hwang, KAERI, Daejeon,Korea (Republic), Ian Miller, GoldSim Technology Group, Issaquah, WA,United States
This paper describes an integrated model developed by the Korean Atomic Energy Research Institute (KAERI) to simulate
options for managing spent nuclear fuel (SNF) in South Korea. A companion paper (Hwang and Miller, 2009) describes a performance
assessment model to address the long-term safety of alternative geological disposal options for different waste streams.
<strong>The</strong> model addresses alternative concepts for storage, transportation, and processing of SNF of different types (CANDU,
PWR), leading up to permanent disposal in geological repositories. It uses the GoldSim software to simulate the logistics of the
associated activities, including the associated capital and operating costs.
<strong>The</strong> model’s results allow direct comparison of alternative waste management concepts, and predict the sizes and timings of
different facilities required. Future versions of the model will also address the uncertainties associated with the different system
components in order to provide risk-based assessments.
2) INTEGRATION OF THE H2 INHIBITION EFFECT OF UO2 MATRIX
DISSOLUTION INTO RADIOLYTIC MODELS - 16239
Yongsoo Hwang, KAERI (Korea); Ian Miller, GoldSim Technology Group (USA)
Different models describing the dissolution mechanism of spent nuclear fuel under repository conditions have been developed
in the last years. One of the most evolved ones is the Matrix Alteration Model (MAM), which is an Alteration/Dissolution source
term model based on the oxidative dissolution of spent fuel. Oxidant and reducing species can be naturally or radiolytically-generated.
<strong>The</strong> experimentally-observed inhibition of matrix dissolution by H2 , was integrated into MAM by considering that H2 is able
to consum the oxidant species responsible for UO2 dissolution, e.g. H2O2 . As a consequence, MAM predicts lower H2O2 concentrations
for systems containing larger amounts of dissolved H2.
On the other hand, radiolysis experiments carried out by Pastina and coworkers have shown that under specific conditions, i.e.
high linear energy transfer (LET) radiation and absence of solid phase, dissolved H2 has a negligible effect on the H2O2 concentration,
thus suggesting that the H2 inhibition effect catalyzed by the matrix surface has not been properly implemented in MAM.
Modelling exercises performed in this work confirms such point and reveals the necessity of considering H2-activation when modelling
this king of systems. In addition, it has been demonstrated that, for high LET radiation, a clear dependence exists between
the extent of the H2 activation and the integral LET of the radiation. <strong>The</strong> integration of the function describing such dependence
allows to improve the implementation of the H2 inhibition effect in MAM.
3) SEPARATION OF LANTHANOID PHOSHATES FROM THE SPENT ELECTROLYTE
OF PYROPROCESSING - 16265
Ippei Amamoto, Hirohide Kofuji, Munetaka Myochin, Japan Atomic Energy Agency (Japan); Tatsuya Tsuzuki, Central
Glass Co.Ltd (Japan); Yasushi Takasaki, Akita University (Japan);Tetsuji Yano, Tokyo Institute of Technology (Japan);
Takayuki Terai, <strong>The</strong> University of Tokyo (Japan)
This study is carried out to make the pyroprocessing hold a competitive advantage from the viewpoint of environmental load
reduction and economical improvement. As one of the measures is to reduce the volume of the high-level radioactive waste, the
phosphate conversion method is applied for removal of fission products from the melt as spent electrolyte in this paper. Though the
removing target elements in the medium are alkali metals, alkaline earth metals and lanthanoid elements, only lanthanoid elements
and lithium form the insoluble phosphates by reaction with Li3PO4 or K3PO4 .
<strong>The</strong>refore, as the first step, the precipitation experiment was carried out to observe the behaviours of elements which form the
insoluble precipitates as double salts other than simple salts. <strong>The</strong>n the filtration was experimented to remove lanthanoid precipitates
in the spent electrolyte using Fe2O3-P2O5 glass system as a filtlation medium which is compatible material with the glassification.
<strong>The</strong> result of separation of lanthanoid precipitates by filtration was effective and attained almost 100%.
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